/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.function.Predicate;

import org.springframework.util.Assert;

/**
 * A filtered {@link ConfigurationPropertySource}.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 */
class FilteredConfigurationPropertiesSource implements ConfigurationPropertySource {

    private final ConfigurationPropertySource source;

    private final Predicate<ConfigurationPropertyName> filter;

    FilteredConfigurationPropertiesSource(ConfigurationPropertySource source,
                                          Predicate<ConfigurationPropertyName> filter) {
        Assert.notNull(source, "Source must not be null");
        Assert.notNull(filter, "Filter must not be null");
        this.source = source;
        this.filter = filter;
    }

    @Override
    public ConfigurationProperty getConfigurationProperty(
            ConfigurationPropertyName name) {
        boolean filtered = getFilter().test(name);
        return filtered ? getSource().getConfigurationProperty(name) : null;
    }

    @Override
    public ConfigurationPropertyState containsDescendantOf(
            ConfigurationPropertyName name) {
        ConfigurationPropertyState result = this.source.containsDescendantOf(name);
        if (result == ConfigurationPropertyState.PRESENT) {
            // We can't be sure a contained descendant won't be filtered
            return ConfigurationPropertyState.UNKNOWN;
        }
        return result;
    }

    @Override
    public Object getUnderlyingSource() {
        return this.source.getUnderlyingSource();
    }

    protected ConfigurationPropertySource getSource() {
        return this.source;
    }

    protected Predicate<ConfigurationPropertyName> getFilter() {
        return this.filter;
    }

    @Override
    public String toString() {
        return this.source.toString() + " (filtered)";
    }

}
